Open AccessImpact of biochar field aging on laboratory greenhouse gas production potentials
Author(s) -
Spokas Kurt A.
Publication year - 2013
Publication title -
gcb bioenergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.378
H-Index - 63
eISSN - 1757-1707
pISSN - 1757-1693
DOI - 10.1111/gcbb.12005
Subject(s) - biochar , mineralization (soil science) , charcoal , greenhouse gas , environmental science , soil water , environmental chemistry , carbon sequestration , weathering , soil conditioner , slash and char , chemistry , pyrolysis , soil science , carbon dioxide , ecology , geology , organic chemistry , geomorphology , biology
Abstract Recent observations of decreased greenhouse gas ( GHG ) production from biochar amended soils have been used to further substantiate the environmental benefit of biochar production and soil incorporation strategies. However, the mechanisms behind this biochar‐mediated response have not been fully elucidated. In addition, the duration of these GHG reductions is not known and is of pivotal importance for the inclusion of biochar into future bioenergy production and climate abatement strategies. In this study, the impacts of biochar field aging on the observed GHG production/consumption were evaluated. Two different wood‐derived biochars and a macadamia nut shell biochar were weathered in an agricultural field in R osemount, MN (2008–2011) and the impacts on net soil GHG production/consumption were assessed through laboratory incubations. For the three biochars evaluated here, weathering negated the suppression of N 2 O production that was originally observed from the fresh biochar in laboratory incubations. On the other hand, all three weathered biochars enhanced CO 2 production (three‐ to tenfold compared with the fresh biochar amendments) in laboratory soil incubations, suggesting an enhanced microbial mineralization rate of the weathered biochar. This enhanced mineralization could be aided by the chemical oxidation of the biochar surfaces during weathering. Fresh biochar reduced observed soil methane oxidation rates, whereas the weathered biochars had no significant impacts on the observed soil methanotrophic activity. This study demonstrates that for these three biochars, weathering greatly alters the GHG response of the soil systems to biochar amendments.